1. Field of the Invention
The present invention relates to a digital data recording apparatus, a digital data recording method, and a computer-readable recording medium for protecting the copyrights of digital data.
2. Description of the Related Art
Thanks to the recent widespread use of the Internet, distribution of music with so-called EC (Electronic Commerce) has been developed, in which desired music data is downloaded from a homepage using a PC (Personal Computer) and the bill for the downloaded music data is charged to a credit card, for instance. The widespread use of music distribution through the Internet using the EC (hereinafter referred to “electronic music distribution” in this specification) would reduce the necessity for consumers to go to record stores and might drastically change the distribution of music, which has been mainly distributed by CDs (Compact Discs).
However, many people listen to music not only at home but also on their way to the office, school, home, and in a car by using a portable playback apparatus and the like. In these cases, music data must be recorded on a portable medium such as an MD (Mini Disc).
Regarding electronic music distribution, delivery companies adopt a variety of encryption methods to protect copyrights. More specifically, a different optimum encryption method is adopted according to the manufacturing company, the distribution route, the usage pattern, and the like. Under these circumstances, when music data that has been distributed through an electronic music distribution system is recorded on an MD, the playback apparatus is required to decode the music data on the MD according to the adopted encryption method. As a result, the playback apparatus is bulky, expensive, and not useful for users.
It is useful for users when music data that has been distributed through an electronic music distribution system is decoded at the time of recording on an MD since playback apparatuses can be inexpensive.
In this case, however, unauthorized duplication of music data is encouraged, and as a result, the copyright of the music data cannot be fully protected.